We confirmed that the Hulu app on the following Fire OS devices(Amazon Fire tablet) works:
- Fire Tablet 7th generation or more
The support for Fire HD 6, Fire HD 7 and Fire HDX 8.9 ended on April 14th. You may continue watching on this device, but it may not work correctly. For more information, please check: [Important] Support for some Fire Tablet ended on April 14th, 2021
*Rooted Amazon Fire tablet or Custom ROM is out of support.
To learn more about how to check the Fire OS version, please check this article: Tablet Device Specifications